Magnetically actuated switch



Aug. 2, 1966 M. BAERMANN MAGNETICALLY ACTUATED SWITCH 3 Sheets-Sheet l Filed July 25, 1964 FIG. 2

l. IM M I.. o S L lu Aug 2, 1966 M. BAERMANN 3,264,424

MAGNETICALLY ACTUATED SWITCH Filed July 25, 1964 FIGA 5 Sheets$h eet 2 I8 \20 INVENTOR.

22 MAx BAERMANN wmsw Aug. 2, 1966 M. BAERMANN 3,264,424

MAGNETI CALLY ACTATED SWITCH Filed July 23, 1964 Sheets-Sheet 3 FIG. 9

l/ l/ k! A) |NVENTOR. MAX BAERMANN Twm Si United States Patent O" 3,264,424 MAGNETICALLY ACTUATED SWITCH Max Baermanu, Cologne, Rhine, Germany (Bensberg Wulfshof, Bezirk Cologne, Germany) Filed July 23, 1964, Ser. No. 384,585 Claims priority, application Germany, Aug. 2, 1963,

B 72,968 l 11 Claims. (Cl. 200-87) In the past various types of switching arrangements have been suggested in which electrical contacts are actuated by a permanent magnet. In many instances,y the switching arrangement is housed in a closed, nonmagnetic housing with a permanent magnet controlling the contacts through the housing. Such arrangements have taken a Variety of structural shapes such as a rotatable permanent magnet which acts upon a similar permanent magnet to operate the contacts within the closed housing.

In some cases, ferromagnetic elements within the housing l are controlled by an external, movable permanent magnet to cause actuation of contacts within the housing.

All of these known switching arrangements have certain disadvantages. The operating components within the switches have a substantial weight; therefore, there v is a tendency for the Icontacts to bev opened orclosed when the housing is jarred by an external blow. This gives a false switching of the contacts within the housing, which can often be detrimental to the device ybeing controlled by the switches. Also, these known switching arrangements have a relatively low sensitivity'and the actuating mechanism outside of thehousing must be very closely spaced with respect to thepactuating elements within the housing to accomplish the desired switching function. In most cases, relatively strong and expensive magnets are required to actuate the switching arrangement within the housing. In many of these prior switching arrangements the switching speed depended upon the speed at which the external actuating magnet'was moved with -respect to the internal operating elements. This prevented rapid making and breaking of the internal contacts and increased the arc erosion of the contacts. In this manner, the effective life of the contacts was substantially decreased.

These and other disadvantages of the prior switching arrangements are completely overcome by the present invention which is directed toward a magnetically controlled electrical switch that is highly sensitive and relatively inexpensive to produce.

In accordance with the present invention, there is provided a magnetically actuated switch comprising a fixed contact, a movable contact, and a biasing mechanism for holding the movable contact in a preselected position. In accordance with the invention the biasing mechanism includes a pair of elongated members extending in generally opposite directions and having ends closely spaced 3,264,424 Patented August 2, 1966 ICC bers and a magnetically permeable element mounted to move with the movable contact and closely spaced from the air gap. In this manner, the magnetized ends of the elongated members attract the magnetically permeable element and hold the movable contact in the preselected position until the elongated members are subjected to an opposing magnetic field. At that time, the movable contact is free to move from the preselected position.

By constructing a switch in accordance with the invention, the spaced elongated members of high permeability material function as magnetic antennas which can concentrate the magnetic lines of force issuing from a permanent magnet field used to actuate the switch. Consequently, even though a relatively small, inexpensive actuating magnet is used, a relatively strong opposing eld is created at the air gap between the elongated members.

By increasing the length of the elongated members or antennas the sensitivity of the switch can be increased. It has been found that if the elongated members are increasedy to a sufficient length, the earths magnetic field can actually actuate the switch because the elongated, high permeability members concentrate a large number of the magnetic lines of force created by the earths magnetic field into the small area of the air gap between the elongated members. This concentration of flux lines is sufficient to create an opposing field in the air gap which will cancel out the magnetic field created by the permanent biasing magnet. In this manner, the movable Contact shifts from its preselected position under the influence of only the earths magnetic field. When such a small actuating field is to be used, the elongated members may have a length of several inches to several feet determined by the flux density of the magnetic field which is to .be used to actuate the switch. The higher the permeability of these elongated members, the higher the ux concentrating effect; therefore, it has been found that nickel-iron alloys having high permeability are extremely Well adapted for construction of these members.

It has been found that a switch constructed in accordance with the present invention is particularly well adapted for various switching applications such as, without limitation, switching housel lights, be they wall mounted or lamps, switching cupboard lights when the cupboard door is opened, actuating safety devices in elevators, indicating when a container is filled, and other similar applications. For instance, it has been found that a switch constructed in accordance with the invention can be used to actuate a table lamp by rotating a permanent magnet lying on the table with the lamp goingon when the magnet is in one position and the lamp going olf when the magnet is in` another position. The use of the elongated, high permeability members, or antennas, makes possible this remote operation of the switch positioned within the table lamp.

When the elongated members are relatively long and the sensitivity of the switch has been increased as indicated above, this switch can be used to indicate the approach of a ferromagnetic body, such as a motor vehicle, ship or the like. With long antennas on the switch, the earths magnetic field can actuate the switch. When the vehicle approaches the switch the earths magnetic field is concentrated or deflected by the ferromagnetic characteristics of the vehicle-so that the earths magnetic field is no longer strong enough to actuate the switch and the switch will return to its normal condition determined by the biasing permanent magnet. This is a further benefit of a switch constructed in accordance with the present invention which is not found in any prior art switch.

Another application of the present invention is in opening a garage door. If a switch constructed in accordance with the invention is positioned under the approach Surface to the garage, the switch can be actuated by an energized electromagnet on an automobile as the automobile approaches the switch.

A particularly advantageous application of a switch constructed in accordance with the present invention 1s the use of the switch to control the light within a refrigerator cabinet. Heretofore, a push button extending through the -housing of the refrigerator was used to4 turn the internal light off when the door was closed. This push button can be eliminated by using the present invention. A switch constructed in accordance with the present invention can be secured within the cabinet frame and adjacent the door closing area. An actuating magnet can be carried by the door so that, when the door closes, the actuating magnet -is close to the switch within the door.

Thus, the switch is operated when the door is closed.

It is appreciated that the incorporation of the magnetic antennas to control the switching of the movable contacts Within the switch arrangement allows the switch arrangement to be used in a variety of other environments although they are not herein specifically discussed.

The primary object of the present invention is the provision of a magnetically actuated electric switch which is economical to produce and durable in use.

Another object of the present invention is the provision of a magnetically actuated electric switch which has a high sensitivity and can be operated by relatively small magnetic fields.

Still another object of the present invention is the provision of a magnetically actuated electric switch which includes two spaced magnetic antennas for concentrating an actuating magnetic field to allow operation of the switch by a relatively small external magnetic field.

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiments of the invention as read in connection with t-he accompanying drawings in which:

FIGURE 1 is a cross-sectional, side elevational view showing, somewhat schematically, the preferred embodi- .ment of the present invention;

FIGURE 2 is a cross-sectional view taken generally along line 2-2 of FIGURE 1 FIGURE 3 is a cross-sectional view somewhat'similar to FIGURE 1 showing the operating characteristics of the preferred embodiment as shown in FIGURE 1;

FIGURE 4 is a schematic illustration of a modification of the preferred embodiment as shown in FIGURES 1-3;

.FIGURE 5 is a cross-sectional, side elevational view showing another means of actuating the preferred embodiment of the present invention as shown in FIGURES 1-3;

FIGURE 6 is a cross-sectional, side elevational view showing, somewhat schematically, a modification of the preferred embodiment of the present invention;

FIGURE 7 is a cross-sectional, side elevational view showing, somewhat schematically, a further modification of the preferred embodiment of the present invention;

FIGURE 8 is a cross-sectional, side elevational view showing,'somewhat schematically, a further embodiment of the present invention;

FIGURE 9 is a cross-sectional view taken generally along line 9-'9 of FIGURE 8; i

FIGURE 10 is a cross-sectional, side elevational view showing, somewhat schematically, another operating arrangement for the preferred embodiment of the present invention as shown in FIGURES 1-3; n I

-FIGURE 11 is a cross-sectional, view taken generally along line 11-11 of FIGURE 12; and,

. FIGURE 12 is a top view showing, somewhat schematically, another modification of the preferred embodivment of the present invention as shown in FIGURES 1-3.

Referring now to the drawings wherein the showings, are

for the purpose of illustrating preferred embodiments of such as Vscrews 16. The magnetic antennas are elongated and have facing ends 18, 20 which dene therebetween an air gap 22 which is coterminous with a biasing, permanent magnet 30 having a north magnetic pole N adjacent end 18 and a south magnetic pole S adjacent end 20.

The antennas 12, 14 are formed from a high permeability material, such as without limitation, an iron-nickel alloy so that the permanent magnet 30 magnetizes the ends 18, 20. T-he length of antennas 12, 14 may be varied according to the sensitivity desired for switch A and this length can vary from approximately an inch to several inches without departing from the spirit of the invention as hereinafter described in detail.

Switch A also includes a fixed contact 32 electrically connected onto lead 34 and secured onto the base 10 directly beneath a movable contact 36 which is secured onto base 10 by a spring member 38. The movable contact 36 is electrically connected onto lead 39 so that closing of contacts-32, 36 establishes an electrical circuit between leads34 and 39. Directly above air gap 22 there is provided a magnetically permeable armature 40 which, in accordance with the preferred embodiment fo the present invention, is formed from a high permeability matelrial and is laminated in construction. The armature 40 includes a downwardly depending leg 42 directly above end 18 and a body 44 adapted to extend over the end 20. There is only a slight 'spacing between the body 44 and t-he antenna 14. The spring member 38 forces the contacts 32, 36 together when in the position shown in FIGURE 1 and the amount of upward movement of member 38 is limited by stop 50. The spring member 38 is stressed to urge armature 40 from the antenna 12; however, the pull of the magnetized end 18, 20 overcomes the spring force of member 38. The amount of spring tension of member 38 is adjusted by adjusting screw 52 extending through antenna 14.

As so far described, the magnetically permeable armature 40 is attracted to the ends 18, 20 by the magnetizing effect of biasing magnet 30. As the member 38 pivots downwardly upon attraction of armature 40 to the ends 18, 20, the movable contact 38 touches the contact 32 before the leg 42 contacts end 18 of antenna 12. Consequently, in the position shown in FIGURE 1, there is la biasing force between the contacts 32, 36. Also, the member 38 applies an upward springing force on armature 40 which is of a lower magnitude than the attraction force between the armature and the ends 18, 20 so that the armature will move into the position shown in FIG- URE l against the inherent resiliency of member 38.

Referring now to FIGURE 3, there is illustrated an actuating magnet assembly 60 including spaced permanent magnets `62, 64 secured onto a body 66 formed from high permeability material. The permanent magnets 62, `64 create a flux field around actuating magnet assembly 60 in a manner somewhat similar to Vthe dashed lines'around assembly v60 in the 'uppermost position of FIGURE 3. In this position, the flux field of the magnet assembly 60 does not affect the condition of th'e switch A.

As the actuating magnet 60 is moved downwardly in FIGURE 3 toward the switch A, the antennas 12, 14 attract and concentrate the flux field created by spaced Ipermanent magnets 62, 64 so that the flux field between these two magnets primarily extends across the air gap 22. By proper selection of the polarity of magnets 62, 64 the flux field created by these magnets in ai-r gap 22 is opposite in polarity to the flux field caused by the biasing magnet 30. When this happens, the two flux elds in the air gap oppose each other and rthey cancel the effec-t of each oth'er on armature 40. At this time, the spring member 38 draws the armature upwardly very rapidly and snaps the movable contact 36 from the fixed contact 32 so that the circuit between leads 34 and 39 is broken. The upward movement of member 38 is cont-rolled or limited by the stop'50 in a manner shown in FIGURE 3.

As the actuating magnet assembly 60 is moved away from the switch A, the fiux field created by permanent magnets 62, `64 is no longer concentrated in air gap 22 and the magnetizing effect of magnet 30 again draws armature 40 downwardly into the position shown in FIG- URE l and the electrical continuity is again established between leads 34 and 39. Since the antennas 12, 14 are high permeability, the residual magnetism within these antennas is not suf'hcient to cancel out the magnetizing effect of magnet '30 between operations of the switch.

The antennas 12, 14 focus the ux lines of the actuating magnet assembly 60 in the air gap 22 so that permanent magnets 62, 64 can have a relatively small flux density and still actuate the switch A in a manner described above. If the antenna-s 12, 14 are increased in length, they become more sensitive and concentrate more flux lines in the air gap. Consequently, if the antennas 12, 14 are extended to a sufficient length they will collect enough flux lines from the earths magnetic field to actuate the switch into the position shown in FIGURE 3. When this happens, it is possible to reestablish the position of switch A as shown in FIGURE l by bringing a ferromagnetic body into close proximity with switch A. This ferromagnetic body will draw the earths flux lines from the antennas 12, 14 so that the flux density created by the earths magnetic eld in ai-r gap 22 will not be sufficient to overcome the magnetizing effect of biasing magnet 30 and the armature 40 will again be drawn into the position shown in FIGURE 1. This operation of switch A greatly enhances the overall versatility of the switch.

Although the switch A as shown in FIGURES 1-3 utilizes normally closed contacts 32, 36, it is appreciated that a contact could be positioned above the contact 36 so that it would be closed when the member 38 snaps into the position shown in FIGURE 3. In this manner, the switch A can be conveniently converted into a normally opened type of switch.

Referring now to FIGURE 5, the switch A can be operated by a permanent magnet 70 having `an upper surface 72 wi-th a south magnetic pole S and a lower surface 74 with a north magnetic pole N. When this magnet 70 is brought into a position close to the antenna 14, the flux field created by magnet 70 is concentrated in air gap 22 so that the armature 40 snaps' away from the antennas 12, 14 in a manner similar to that discussed in connection with FIGURES 1-3. Since the operation of the switch as shown in FIGURE 5 does not substantially depart from the operation of the switch as shown in FIGURES 1-3, further discussion of this operation is not necessary.

In FIGURE 4, a modification of the antennas 12, 14 is illustrated. In this modification, antennas 80, 82 are truncated -in shape with small ends 84, 86 facing each other to define an air gap S8. The truncated construction of the antennas allows a lgreater area of antenna lto draw the lines of force from an external field; therefore, concentration of the flux lines in the air gap 88 is inc-reased. When the flux density betwe'en ends 84, '86

`is sufficiently strong to overcome the flux density created by biasing magnet 30, the switch A, incorporating antennas 80, 82 is operated in a manner discussed in connection with the embodiment shown in FIGURES l-3.

Referring now to FIGURE 6, a biasing magnet 90 is secured onto antenna `14 with the south magnetic pole S abutting the antenna 14 and the north magnetic pole N facing upwardly toward armature 40. In this manner, the air gap 22 is in a magnetic circuit including -the two antennas 12, 14, the armature 40, the magnet 90 and the air space between the magnet 90 and body y44 of armature 40. Since the air gap is within the magnetic circuit, when an opposing magnetic field is concentrated in the air gap by the antennas 12, 14 the switch as shown in FIGURE 6 will operate in a manner similar to switch A shown in FIGURES l-3. When the armature 40 is in its downwardmost position, there is very little spacing between the biasing magnet and the armature so that relatively little magnetic losses are caused by the reluctance in this space. Th'e same is true of the spacing between the armature 40 and the antenna 14 in FIGURES 1-3 and 10. The leg 42 in the switch lof FIGURE 6 is somewhat Ilonger than the leg 42 in the other embodiments of the invention to accommodate the thickness of biasing magnet 90.

Another embodiment of th'e present invention is illustrated in FIGURE 7 wherein biasing magnet 109 is secured onto the spring member 38 so that the magnet performs both the function of the biasing magnet and the function of the magnetically permeable armature 49. When the contacts 32, '36 are closed, as shown in FIGURE 7, the magnet 100 'creates a magnetic circuit including the air gap 22. Consequently, when the antennas 12, 14 a-re subjected to an external magnetic field, the opposing magnetic field created within the air gap tends to overcome the magnetic field caused by magnet 100 so that the spring member 38 snaps upwardly to disengage contacts 32, 36. Basically, the operation of the switch is not substantially different from the operation of switch A as shown in FIGURES 1-3 and 10.

Another embodiment of the present invention is shown in FIGURE 8 wherein a permanent biasing magnet 110 is fixedly positioned above the switch and the armature `40 is replaced by two pole pieces 112, 114 with the pole pieces being closely spaced with respect to the magnetic poles of magnet 110. The pole piece 112 has a downwardly extending leg 116 which performs the function of leg 42 in the previously described embodiments of the invention. The magnet creates a flux circuit -through the pole pieces and across the air gap 22. The pole pieces are formed of high permeability material so that the pole pieces are attracted to the antennas 12, 14 in a manner similar to the attraction of armature 40 to the an-tennas 12, 14. Again, an opposing eld will be concentrated by the antennas 12, 14 in the air gap 22 so that this opposing field can overcome the field created by magnet 110 and allow the spring member 38 to snap the contacts 32, 36 from engagement.

In FIGURE 10, there is illustrated an arrangement for actuating switch A of the type disclo-sed in F-IGURES 1-3. In this lfigure, a nonmagnetic tube 110 which may be the stem or post of an electric lamp, is provided with stops 122, 124 and an annular magnet 126, which is axially magnetized, is adapted to move between these stops. When the magnet 126 is in the position shown by the solid lines in FIGURE 10, the magnet does not create a -circuit through air gap 22; and, the switch A is in the position shown in FIGURES 1 and l0. When the magnet 126 is moved to the left, in FIGURE 10, into engagement with stop 122, the -magnet lthen creates an opposing magnetic field within the air gap 22 so that the contact 36 is snapped Aaway from the contact 32 in the manner pr viously described. Consequently, this arrangement provides a convenient remote control for the actuation of switch A.

Referring now to FIGURES 11 and 12, a further embodiment of the present invention is illustrated. A non- .magnetic, cup-shaped body 130 is adapted to support L- shaped antennas 132, 134 that define an air gap 13S. Between the ends of the antennas 132, 134 there is provided an arcuately shaped permanent biasing magnet 136 having a north magnetic pole N and a south magnetic pole S in contact with the ends of the antennas. A fixed contact 140 is secured onto body 130 and a movable contact 142 is adapted to selectively engage the fixed contact. In this manner, an electrical circuit is made and broken between leads 144, 146. The movable contact 142 is carried by a plunger 148 having at its upper end a plate 150 which forms a stop for compression spring 152 so that the plunger 148 is biased upwardly by the spring. At the upper end of plunger 148 there is provided a high permeability magnet armature 160 which is attracted to the antennas 1-32, 134 by Ithe flux field created by magnet 136. Surrounding the body 130 is an annular magnet 170 which is diametrically magnetized to provide a north magnetic pole N on one side and a south magnetic pole S on the opposite side. When the magnet 170 is rotated so that the poles face Ithe antennas 132, 134, the magnet 170 creates an opposing field within the air gap 135 and the armature 160 is released from the antennas 132, 134 so that the spring 152 can'move the plunger 148 in an upward direction. This breaks the contact between contacts 140, 142 and opens the circuit between leads 144, 146. When the magnet 170 is rotated 90 with respect to the antennas 132, 134, the armature is again attracted to the antenna and the contacts 140, 142 are closed.

A variety of magnetic materials could be utilized for the actuating and/ or biasing magnets as described herein; however, in accordance with the preferred embodiment of the present invention, these magnets are formed from particles of barium ferrite, strontium ferrite, lead ferrite, or bismuth-manganese embedded within and bonded together by a plastic or rubber binder.

The Ibiasing magnets which are used to create a magnetic circuit including the air gap 22 may be rotated or otherwise shifted to change the amount of biasing flux within the air gap 22. In this manner, the amount of flux necessary for operating the switch can be conveniently varied. In addition, it is appreciated that Ithe switch can be enclosed within a non-magnetic housing so that contaminating materials can be excluded from the operating elements of the switch. When such a housing is used, a protective gas can be sealed within the housing to further protect -the operating elements of the switch. All of these features are within the contemplation of the invention.

The present invention has been described in connection with several embodiments and it is to be appreciated that various structural changes may be made in these embodiments .without departing from the intended spirit and scope of the present invention as defined in the appended claims.

Having thus described my invention, I claim:

1. A magnetically actuated switch comprising a fixed contact, a movable contact, a biasing mechanism for holding said movable contact in a preselected position with respect to said fixed contact, and means for urging said movable contact from said preselected position, the urging effect of said means being less than the biasing effect of said biasing mechanism, said biasing mechanism including a pair of fiat, elongated antenna members mounted in generally the same plane and extending in generally opposite directions and having ends closely spaced to define an air gap between said elongated members, said elongated members being formed of high permeability material, and a permanent magnet with at least a pair of opposite polarity magnetic poles being positioned adjacent said air gap to magnetize said ends with opposite magnetic poles and a magnetically permeable element mounted to move with said movable contact and being closely spaced from said air gap whereby said magnetized ends of said elongated members attract said element and hold said movable contact in said preselected position until said elongated members are subjected to an opposing magnetic field at which time said urging means move said movable contact and element from said preselected position.

2. A switch as defined in claim 1 wherein said urging means is a spring member and said movable contact and permeable element are mounted on said spring member, said biasing mechanism flexing said spring member when said movable contact is in the preselected position so that said spring member can move said movable contact from said preselected position when said elongated members are subject to said opposing magnetic field.

3. A switch as defined in claim 2 wherein said preselected position is when said movable contact is in elec- 4. A switch as defined in claim 1 wherein said permanent magnet is fixedly located with respect to the ends of said elongated members and is coterminous with said air gap and said magnet has one magnetic pole against one of said ends and an opposite polarity pole against the other of said ends.

5. A switch as defined in claim 1 wherein said permanent magnet is xedly located on one of said elongated members with one of said magnetic poles in contact with said elongated member and the other of said magnetic poles spaced from said elongated member and facing said magnetically permeable element.

6. A switch as defined in claim 1 wherein said movable contact is carried by a movable element and said permanent magnet is attached `to said movable element with one magnetic pole facing one `of said ends and the other magnetic pole facing the other of said ends.

7. A switch as defined in claim 1 wherein said movable contact is carried by a movable member, said magnetically permeable element having first and second pole pieces, said permanent magnet being located between said pole pieces with one of said magnetic poles facing each of said pole pieces and premagnetizing said ends through said pole pieces.

8. A magnetically actuated switch comprising a fixed contact, a movable contact, a biasing mechanism for holding said movable contact in a preselected position with respect to said fixed contact, and means for urging said movable contact from said preselected position, the urging effect of said means being less than the biasing effect of said biasing mechanism, said biasing mechanism including a pair of elongated members extending in generally opposite directions and having ends closely spaced to define an air gap between said elongated members, said elongated members being formed of high permeability material, and a permanent magnet with at least a pair of opposite polarity magnetic poles being positioned adjacent said air gap to magnetize said ends with opposite magnetic poles and a magnetically permeable element mounted to move with said movable contact and being closely spaced from said air gap whereby said magnetized ends of said elongated members attract said element and hold said movable contact in said preselected position until said elongated members are subjected to an opposing magnetic eld at which time said urging means move said movable contact and element from said preselected position, a nonmagnetic, tubular housing surrounding said switch and an annular, actuating magnet slidably received on said housing, said magnet being axially magnetized with one magnet pole adjacent each end thereof, said magnet being slidable between a first position remote of said air gap and a -second position adjacent said air gap in which second position the biasing action of said biasing mechanism is overcome by said actuating magnet.

9. A magnetically actuated switch comprising a fixed contact, a movable contact, a biasing mechanism for holding said movable contact in a preselected position with respect to -said fixed contact, and means for urging said movable contact from said preselected position, the urging effect of said means being less than the biasing effect of said biasing mechanism, said biasing mechanism including a pair of elongated members extending in generally opposite directions and having ends closely spaced to dene an air gap between said elongated members, said elongated members being formed of high permeability material, and a permanent magnet with at least a pair of opposite polarity magnetic poles being positioned adjacent said air gap .to magnetize said ends with opposite magnetic poles and a magnetically permeable element mounted to move with said movable contact and being closely spaced from said air gap whereby said magnetized ends of said elongated members attract said element and hold said movable contact in said preselected position until said elongated members are subjected to an opposing magnetic eld at which time said urging means move said movable contact and element from said preselected position, an annular actuating magnet surrounding said switch and having a pair of diametrically spaced magnetic poles and means for rotating said actuating magnet into a position with the poles adjacent said elongated members to overcome the biasing action of said biasing mechanism.

10. A magnetically actuated switch comprising a Xed contact, a movable contact mounted on a movable member and adapted to be selectively moved into and out of engagement with -said xed contact as said movable member is moved, a pair of flat, elongated antenna members mounted in generally the same plane and extending in generally opposite directions and having ends closely spaced to define an air gap between said elongated members, said elongated members being formed of high permeability material, a permanent magnet with at least a pair of opposite polarity magnetic poles being positioned adjacent said air gap to magnetize said end-s of said elongated members, and a magnetically permeable element mounted on said movable member and closely spaced from said air gap whereby said magnetized ends of said elongated members attract said element until said elongated members are subjected to an opposing magnetic eld.

11. A magnetically actuated switch comprising a fixed contact, a movable member with a magnetically permeable element, a movable contact secured onto said movable member and adapted to selectively contact said fixed contact, a pair of elongated members extending in opposite directions and having ends closely spaced to define an air gap between said elongated members, said elongated members being formed of high permeability material, said magnetically permeable elements being closely spaced from said air gap, a permanent magnet adjacent said air gap to magnetize said ends, an annular actuating magnet surrounding said elongated members and radially magnetized to have diametrically spaced magnetic poles, means for rotatably mounting said actuating magnet to selectively bring said pole into magnetic proximity to said elongated members to oppose the magnetization of said ends and spring means for biasing said movable member away from said pole ends, said biasing effect of said spring means being less than the magnetic pull of said magnetized ends.

References Cited by the Examiner UNITED STATES PATENTS 3,067,3 05 12/1962 Stout et al 20G-87 3,134,870 5/1964 Reed et al 200--87 3,172,976 3/1965 Abel ZOO-87 OTHER REFERENCES German printed application, Bauder, 1,114,886, 10/ 12/ 1961. I

BERNARD A. GILHEANY, Primary Examiner.

B. DOBECK, Assistant Examiner. 

10. A MAGNETICALLY ACTUATED SWITCH COMPRISING A FIXED CONTACT, A MOVABLE CONTACT MOUNTED ON A MOVABLE MEMBER AND ADAPTED TO BE SELECTIVELY MOVED INTO AND OUT OF ENGAGEMENT WITH SAID FIXED CONTACT AS SAID MOVABLE MEMBER IS MOVED, A PAIR OF FLAT, ELONGATED ANTENNA MEMBERS MOUNTED IN GENERALLY THE SAME PLANE AND EXTENDING IN GENERALLY OPPOSITE DIRECTIONS AND HAVING ENDS CLOSELY SPACED TO DEFINE AN AIR GAP BETWEEN SAID ELONGATED MEMBERS, SAID ELONGATED MEMBERS BEING FORMED WITH AT LEAST A PAIR OF MATERIAL, A PERMANENT MAGNET WITH AT LEAST A PAIR OF OPPOSITE POLARITY MAGNETIC POLES BEING POSITIONED ADJACENT SAID AIR GAP TO MAGNETIZE SAID ENDS OF SAID ELONGATED MEMBERS, AND A MAGNETICALLY PERMEABLE ELEMENT MOUNTED ON SAID MOVABLE MEMBER AND CLOSELY SPACED FROM SAID 